1. Field of the Invention
This invention pertains generally to devices for manipulation of particles, and more particularly to optoelectronic tweezers.
2. Description of Related Art
Optically-induced dielectrophoresis, or optoelectronic tweezers (OET), provide a powerful, flexible method of manipulating microparticles and cells. In state of the art OET devices, the electric field is perpendicular to the photosensitive electrode surface. However, it is sometimes advantageous to have an electric field that is parallel to the photosensitive surface of the OET device. Rod-shaped particles, such as E. coli bacteria, align in parallel with the vertical electric field during the OET manipulation. In order to observe the long axis of rod-shaped particles, it is necessary to create an electric field in the lateral direction. Furthermore, such a device would only require a single, photosensitive electrode surface, allowing greater flexibility for OET device integration.
The following publications and patents provide additional background and are incorporated by reference in their entirety:    P. Y. Chiou, A. T. Ohta, and M. C. Wu, Nature, vol. 436, pp. 370-372, 2005.    P. Y. Chiou, W. Wong, J. C. Liao, and M. C. Wu, IEEE International Conference on Micro Electro Mechanical Systems (MEMS), 2004.    G. J. Shah, P. Y. Chiou, J. Gong, A. T. Ohta, J. B. Chou, M. C. Wu, and C-J. Kim, 19th IEEE International Conference on Micro Electro Mechanical Systems, 2006.    P. Y. Chiou, A. T. Ohta, M. C. Wu, IEEE/LEOS International Conference on Optical MEMS, 2005.    A. T. Ohta, et al., International Conference on Bio-Nano-Informatics (BNI) Fusion, 2005.    J. Voldman, “Electrical Force for Microscale Cell Manipulation”, Annu. Rev. Biomed. Eng., vol. 8, pp. 425, 2006.    K. C. Neuman, E. H. Chadd, G. F. Liou, K. Bergman, and S. M. Block, “Characterization of photodamage to Escherichia coli in optical traps,” Biophys. J., vol. 77, pp. 2856-2863, 1999.    U.S. Pat. No. 7,088,116; U.S. Pat. No. 7,092,046; U.S. Pat. No. 7,084,471; U.S. Pat. No. 6,958,132; U.S. Pat. No. 6,903,432; U.S. Pat. No. 6,878,961; U.S. Pat. No. 6,872,588; and U.S. Pat. No. 6,798,033.